text: One dramatic source of man-made radioactivity is a nuclear weapons test. The glassy trinitite created by the first atom bomb contains radioisotopes formed by neutron activation and nuclear fission.  In addition some natural radioisotopes are present.  A recent paper reports the levels of long-lived radioisotopes in the trinitite. The trinitite was formed from feldspar and quartz which were melted by the heat. Two samples of trinitite were used, the first (left-hand-side bars in the graph) was taken from between 40 and 65 meters of ground zero while the other sample was taken from further away from the ground zero point.
  The Eu (half life 13.54 year) and Eu (half life 8.59 year) were mainly formed by the neutron activation of the europium in the soil, it is clear that the level of radioactivity for these isotopes is highest where the neutron dose to the soil was larger.  Some of the Co (half life 5.27 year) is generated by activation of the cobalt in the soil, but some was also generated by the activation of the cobalt in the steel (100 foot) tower.  This Co from the tower would have been scattered over the site reducing the difference in the soil levels.
  The Ba (half life 10.5 year) and Am (half life 432.6 year) are due to the neutron activation of barium and plutonium inside the bomb.  The barium was present in the form of the nitrate in the chemical explosives used while the plutonium was the fissile fuel used.
  The Cs level is higher in the sample that was further away from the ground zero point &ndash; this is thought to be because the precursors to the Cs (I and Xe) and, to a lesser degree, the caesium itself are volatile. The natural radioisotopes in the glass are about the same in both locations.